The relevant paragraph asked:
I was wondering if you may know where I can find some material on Eastern Orthodox Christianity (critique mainly), as I've lately been confronted with a lot of opposition from orthodox Christians defending their faith during debates with the "oh, we're not like them (catholics, protestants), our teachings bring only peace and prosperity and we didn't have any Crusades, et cetera..." argument. But I'm more than certain that there actually were executions and burning at the stake ordered by the Orthodox Church (but I can't find 'em!), so if you could give me a brief list (articles or sites) I'd be uber happy.
No, I don't know of any specific works regarding Orthodox Christianity, although I'm sure you can find some. As I have recently grown fond of pointing out, there are 38,000 sects of Christianity. Debunking every one of them individually would be a pretty time consuming task. If I wanted to see the history of a particular church, I would probably start at Wikipedia and search outward from there.
Rather than reject the whole thing as a package deal, in your situation I would fall back on Matt's favorite question: "Tell me what you believe, why you believe it, and why I should believe it?" It's one thing to speak in generalities about how Christian offshoot X is "not like those other Christians"; it's another thing entirely to identify the individual beliefs and try to defend them.
Personally, I couldn't care less how many atrocities this or that group committed, as opposed to some other group. It's not as interesting to me as finding out whether they make claims that are true, and how they think they know that the claims are true. What you'll probably find on further investigation is that they believe many of the same unsupportable things all religions believe: That you can't explain the complexity of life without a god, that somebody had to start it all, that it feels nicer to believe in a higher power, etc., etc.
If you can get them to bring these up, you are on much more solid ground. Instead of having to denounce an entire group based on the actions of some representative -- which always makes you look mean! -- you can go after the arguments on their merits. At that point, I'd refer to something like Iron Chariots, or Guy Harrison's book, for ideas to respond to those claims.